1. Field of the Invention
The present invention is directed to a light distributor for an x-ray diagnostics installation for directing light from the output screen of an x-ray image intensifier onto a plurality of pick-up components, such as cameras attached to the housing of the light distributor.
2. Related Application
The subject matter of the present application is related to the subject matter of co-pending U.S. application Ser. No. 216,201, filed July 7, 1988 (Arthur Gall and Karl Weiss) entitled "Light Distributor For An X-Ray Diagnostics Installation."
3. Description of the Prior Art
For displaying and/or permanently recording x-ray images in an x-ray diagnostics installation, various different types of pick-up components, such as cameras, are arranged to receive the light, corresponding to an x-ray image, from the output screen of an x-ray image intensifier. Frequently more than one type of display and/or recording is desired, such as, for example, a video display, a moving picture (strip film) or a photographic picture (sheet film). Thus as many as three cameras, namely a video camera, a motion picture camera and a photographic camera, may be necessary to couple to the x-ray image intensifier to obtain all of the desired formats. Image recording via these pick-up components may be undertaken simultaneously or in sequence. This requires that the light from the output screen of the x-ray image intensifier be divided or distributed so as to reach each of the pick-up components.
A light distributor is disclosed in U.S. Pat. No. 4,383,328 which distributes the light from the output image of an x-ray image intensifier onto two motion pictures cameras and onto one video camera. A pivotable, semi-reflective mirror splits the light from the output screen of the image intensifier onto the two motion picture cameras. The pivotable mirror, however, remains within the beam path of one of the motion picture cameras in its standby position. A 100% reflecting mirror can be disposed in front of the pivotable mirror in its standby position, the reflecting mirror being disposed perpendicularly relative to the beam path of x-ray image intensifier. A mirror arrangement having a rotatable mirror tilted at a angle of 45% and having a reflection of 90% can be introduced into the beam path in front of the 100% reflecting mirror, the rotatable mirror permitting selecting deflection of the beam path onto one of the motion picture cameras or onto the video camera.
One purpose of the light distributor disclosed in U.S. Pat. No. 4,383,328 is to provide a more compact structure in comparison to previously known light distributors, so that the vertex distances of the lenses of the motion picture cameras relative to the input optics which receives the light from the x-ray image intensifier can be maintained small in order to achieve a good image quality. This is important because light losses increase with an increase in the vertex distance of the lens. In the structure of U.S. Pat. No. 4,383,328, however, the introduction of mirrors following each other in different planes in the beam path still undesirably increases the vertex distance. Moreover, it is difficult to maintain pivotable mirrors as used in the structure of U.S. Pat. No. 4,383,238 stable against jolts during operation. Additionally, this known light distributor must include a plurality of motors for actuating the mirrors, giving the light distributor a relatively complicated structure and a relatively high weight. Moreover, the structural length of the combination consisting of the x-ray image intensifier and the pick-up components is increased, since one of the pick-up components, for example the first motion picture camera, is situated in the direct beam path of the x-ray image intensifier. In some instances, the height of the examination room in which the installation is contained will not be sufficient, given the use of devices disposed beneath the patient support table, and the presence of an additionally ceiling support, which further add to the overall height of the combination.